#类名开头相同的通用样式
snippet *
	[class^="${1:common}-"], 
	[class*=" $1-"] {
		$0
	}
snippet .trangle-down
	.trangle-down {
		width: 0;
		height: 0;
		border-left: 50px solid transparent;
		border-right: 50px solid transparent;
		border-top: 100px solid red;
	}
